Finally, angles (in degrees) can also be entered in decimal form (27° 31.1´ = 27.5183). Index correction: -3.3′, entered as – 33/600 in cell B2 19:49:50    75º 58.6′    76º 19.0′    115º 55.0′     N 21º 08.9′    1.0A            164.9 Skip to Navigation Skip to the Content of this Page Back to the Accessibility Menu. According to the intercept method of Marcq St. Hilaire a celestial line of position (LOP) is plotted on a chart as the line perpendicular to the azimuth line at the intercept distance toward or away the geographical position (GP) from the assumed position (AP). HP (in arcminutes from moon.xls cell C8): 55.1 entered in cell E6, Sextant altitude (Hs): 25º 21.6′, entered as 25 216/600 in cell B1 The lessons presented are meant to be taken in order by lesson number to work your way through the course. 34.403
º For altitudes above 15°, a simplified formula is adequate (± 0’.02) Refraction = 0.96/ Tan (Altitude) Refraction tables make assumptions on the layers for low altitudes and should be Ephemerides for the planet Uranus (along with Neptune and Mercury) are not listed in celestial navigation almanacs, as these objects are not suitable for astronavigation purposes. Considering the difficulties I had with the index error determination I was in fact a bit worried before I started the calculations. Location: 35° 53’ N, 106° 19’ W, Sun: In the following example I took a series of Sun sights not long before the Local Apparent Noon (LAN). The main purpose of this calculator is to facilitate the practice of celestial navigation at sea. there is also a rather good excel celestial spreadsheet here. In two separate NavList postings Greg Rudzinski recently published his technique of using the T-Plotter in constructing such an LOP. As such, its use is not limited to observations of celestial bodies. Navigation worksheets for celestial navigation, deduced reckoning, etc. Subtracting the Moon semidiameter (16.4′) from the topocentric centered lunar distance of 2° 15.6′ yields a value that is very close to 2 degrees. UT               Hs               Ho               GHA            Declination   Intercept    Azimuth, UT             Hs              Ho             GHA            Declination   Intercept    Azimuth, 19:57:30    76º 14.8′    76º 35.2′    117º 50.0′     N 21º 08.8′    3.4A            172.5, Two-body fix (Santa Barbara, 16 July 2011). Comparisons with the 2016 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2016 without the need for any changes or updates. … Temperature (cells E3, F3): 10 degrees Celsius Assumed position (AP) is taken to be the dead-reckoning (DR) position: Sextant: Astra III Professional with the 7×35 Celestaire telescope 2015 Nautical Almanac Commercial Edition mentions the two planets in its “Do Not Confuse” paragraph on page 8. Presetting the sextant to: 90° 36.4’. The T-Plotter Basic model is imprinted with a grid that fits the VP-OS (Universal) Plotting Sheets, on which 20 nautical miles are represented by 1 inch. Sextant is affected by errors. Keep a deduced reckoning (DR) track on a chart using course steered and the Distance-Speed-Time formula 60D = ST. 2. Pressure (cell E2): 1010 mb Nevertheless, James took morning sights to confirm the island of landfall. Spreadsheets aries_stars.xls and what_star.xls were modified with the changed spelling of one star’s name (Alnair). 63-65. Celestial Navigation Software for PCs, Calculators and iPod/iPhone Apps Each version of StarPilot is a state of the art celestial navigation calculator which makes navigation by the stars easy for the expert or novice marine navigator. 17:50:30      57° 22.4′     57° 43.1′      86° 06.4′      N 21° 19.8′       2.1A         105.0. These coordinates were used as the “assumed position” (AP) in the subsequent calculations of intercepts and azimuths. StarPilot then asks for the sight time, and date, body name, DR Lat and Lon, as well as the Index Correction and Height of Eye. Artificial horizon was not used: entered N in cell B4 In the following image we can indeed see a rather convincing arc that would peak shortly after 20h UT. In Southern Latitudes. UT               Hs               Ho               GHA            Declination   Intercept    Azimuth Input: celestial functions in VBA. retain the "big picture" of celestial navigation. 17:47:50      56° 51.6′     57° 12.3′      85° 26.4′      N 21° 19.8′       1.0A         104.4 I made the following worksheets to make navigating small sailboats easier, safer, and more accurate. The four morning sights were averaged to produce a single effective data point, whose LOP was then crossed with the LOP from the afternoon sight to obtain a fix. These pages can be printed, photo copied, and bound in books to be used on passages. Almanac spreadsheets in 2019. At the fifth anniversary of our website’s launch we review some of Navigation Spreadsheets functions. With a Moon crescent in the vicinity of the two planets, it has been mentioned that Uranus is also in the area, separated from the Moon limb by about 2 degrees. Hs: 25º 21.6′ The data for the following example are from John Karl’s “Celestial navigation in the GPS age” (First Edition, 2007), pp. intercept.xls UT: 02h 19m 14s Formulas and functions are also supported. 19:35:30    74º 55.4     75º 15.8′    112º 20.0′     N 21º 09.0′    1.1T            152.0 Another alternative is to enter these values using the formula bar as: = 27 + 311/600. Comparisons with the 2021 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2021 without the need for any changes or updates in the calculations. LHA greater than 180°....Zn=Z. All cells of the workbook are protected except for the yellow user data entry cells. 19:43:00    75º 34.0′    75º 54.4′    114º 12.5′     N 21º 08.9′    0.9T            158.5 17:42:30      55° 48.2′     56° 08.9′      84° 06.4′      N 21° 19.9′       0.4A         103.3 Height of eye above the sea level : 2,5 meters. the AP’s parallel at 56 NM east of the AP, The sextant is a device for measuring angles between two lines of sight. Determine the direction of the Celestial Body (CB): Use the compass at center of paper, mark the Azimuth (Zn) of the Celestial Body (CB), clockwise from north. SD: 15.8’, Moon: 19:37:55    75º 09.4′    75º 29.8′    112º 56.2′     N 21º 09.0′    1.5T            154.1 Longitude: E 161º 43′, entered as (+) 161 43/60 in cell B2, GP of Moon from row 5 of moon.xls: Click here to view a demonstration video of how T-Plotter Basic can be used to plot celestial LOPs. From BackBearing.com ‣ Complete Celestial Sight Reduction Excel … Then, I pointed the sextant at the Moon and soon the Sun appeared right on top of Moon’s limb, as expected. The spreadsheet sailings.xls can be used in this case, since the angle of 1 minute of arc corresponds to the distance of 1 nautical mile on the surface of the Earth. Navigation calculation is a means of determining the position of one’s vessel, by sighting a celestial body in the open sea where land is not visible. The results are computed by noon_motion.xls to be: One generally expects getting a very accurate latitude value and not-so-great longitude value from meridian-transit observations. The intercept distances are small as expected, since they were calculated using the known position as the AP. Observed altitudes (Ho) were obtained from the recorded sextant altitudes (Hs) with alt_corr.xls; see the first data point as an example (these were lower-limb observations, hence the SD correction is positive). declination S 27° 31.1´), then in the formula you must use minus signs for both the whole degree component and its fraction: =-27-311/600. The app work totally off-line, can use gps position for calculation and can export calculation data with charts in pdf file. to which we add Ho = 30º 30.0’ in order to allow the calculation of the intercept and the plotting of the LOP. Nautical Calculator is an excellent tools, which covers every aspect of nautical and astronomical navigation and solves every concerning spherical-trigonometrical problem. If the value is negative (e.g. For instance, the angle between two landmarks can be observed, which (via the central angle theorem), confines the vessel to a circular line of position. The two LOP intersections can be computed either with spreadsheet lops.xls or two_body_fix.xls. While in the first example the parallaxes were essentially negligible (and hence the sailings.xls spreadsheet could be used to calculate the Venus-Mars angular separation), this is not the case for the Moon. See screenshots, read the latest customer reviews, and compare ratings for Celestial Navigation Data Calculator. The azimuths approach the meridian passage value of 180º but stop just short of it due to reasons explained above. UT               Hs               Ho               GHA            Declination   Intercept    Azimuth In addition, the noon_motion.xls spreadsheet is also capable of addressing the construction of this curve on a moving vessel; in this case the speed is zero since I made the observations from a fixed location. + off - on DIP-HE ft UTC h m s Ha ° ´ DR Lon ZD +W -E UTC date / LOP label GHA hr. This book is dedicated to removing the cloak of mystery; to teach the concepts, some interesting history, the techniques, and computational methods using the simple pocket scientific calculator. Online Navigation Calculators compiled by Starpath School of Navigation. "This celestial navigation software allows the reduction of sextant sights. is to enter these values using the formula bar as: =27+311/600. SeaSources Celestial Navigation Training Videos This course is designed to help you prepare yourself to pass the U. S. Coast Guard examination on Celestial Navigation for the upon oceans endorsement. Another way (independent of Hc) "L” is latitude and “d” is declination. Its horizontal parallax (HP) is twice that of Venus, so current Earth-Venus distance is about twice the current Earth-Mercury distance. The “Blank” version of the T-Plotter facilitates the plotting of LOPs on charts of any scale. In the past I have observed that the parabolic fitting employed by these spreadsheets works very well if the data actually straddle the culmination point. A recent trip to Santa Barbara, California, presented me with an opportunity to do some sights and calculations. Body: Moon, lower limb Using this value as the “Scatter” parameter in the weighted least-squares fitting procedure (average2.xls: fitted, not precomputed slope), all weights came out equal, so this procedure resulted in calculating the simple average of UT’s and Ho’s. DR position : Latitude 38°34,2’ North – Longitude 005°32,7’ East. 249 or Pub. Date: 11 May 2005 W 119º 41.64′    i.e. Last but not least, celestial navigation may be a highly appreciated alternative if a GPS receiver happens to fail. This plot has the Ho’s on the y-axis. Intercept (cells D6, E6): 1.8 Toward (difference of only 0.2′) This prevents the inadvertent modification of cells containing formulas use to calculate the results. In Northern Latitudes. For additional specification and ordering information, visit: The recently extended spreadsheet intercept.xls: can be used in alternative ways to plot the same line of position (LOP), as shown in this demonstration video. GP: GHA = 53º    Dec = S 15º All three examples are taken from the 2014 Nautical Almanac Commercial Edition. Steps required for Standard Navigation: 1. Height of eye: 9 feet 16 July 2011 (Sun: afternoon):  T=26 ºC,  P=1010 mb,  Index Correction=0.0′,  Height of eye=6 ft Input: Hs = 4º 32.6’ Note that there is no need for increments and corrections (v or d Corrn). GHA: 182 254/600 entered in cell C2 Comparisons with the 2018 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2018 without the need for any changes or updates.   A good result overall. LHA greater than 180°....Zn= 180° – Z. LHA less than 180°...........Zn= 180° + Z. ... STAR ALTITUDE - useful for Celestial Navigation. LHA less than 180°...........Zn=360° – Z. 279-280). Uranus appears slightly to the west of the (almost new) Moon crescent, so the interesting quantity is its distance from Moon’s illuminated near limb. 21:18:20      69° 00.6′     69° 13.6′     138° 03.7′     N 21° 18.4′       1.6T          235.8. the AP’s meridian at 52 NM north of the AP TAMAYA Navigation Calculator 〈NC-2200〉 The NC-2200 is a navigation calculator capable of performing complicated navigation calculation and astro-navigation calculation, with speed and accuracy. Celestial Navigation. Navigation was now line of sight, with the northern peak of the island in clear view. Spreadsheets mercury.xls and venus.xls show that the geographic positions (GP) of the two planets are very close to each other at this time. Becky had already retrieved the local charts, given the confidence of their previous celestial fixes and dead reckoning over the night. UT               Hs               Ho               GHA            Declination   Intercept    Azimuth Observation point: Universal Time: 15:25 19:33:30    74º 38.4′    74º 58.8′    111º 50.0′     N 21º 09.0′     4.0A           150.4 Spreadsheet::WriteExcel module is can be used to create native Excel binary files. GP (row 5) The data from this example are summarized in the worksheet below; input data are marked as green, and spreadsheet results (some of which are relayed as input for subsequent calculations) are blue. The error of fix and the standard deviation of intercepts are interestingly similar at about 2 nm. Comparisons with the 2020 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2020 without the need for any changes or updates. ... on the phase of the moon! The formula is: T = (JD - 2451545 ) / 36525. SD (in degrees from moon.xls cell A8): entered (+)15/60 (positive for lower limb observations) in cell B11, Output: 1) Ephemeris (almanac data), Venus GP on 2014 May 5 at 13h 15m 18s (p. 256): 2) Sextant altitude corrections (Venus, p. 259), alt_corr_xls With three spreadsheets we reproduce the computations for the sight reduction of the Moon observation presented in Figure 6.4 on p. Formatted text and numbers can be written to multiple worksheets in a workbook. A secondary purpose is to provide the solutions of a spherical triangle of which two sides and the included angle are known and it is necessary to find the values of the third side and adjacent angle. -119.694
º. AP: Lat = N 32º    Long = W 16º In cells A2-F2 entered: 2005 5 11 2 19 14, Output: This computed result is not as good but it is still reasonable, especially since it came from a data set that stopped short of LAN and hence had to be extrapolated. Output: Ho = 4º 17.6’, 3) The calculated altitude and azimuth (pp. GHA: 182º 25.4′ (same as 181º 85.4′ in the book) celestial navigation, excel, Moon, Sun. 63-65. The spreadsheet is password protected to … Subtracting the sum of the two semidiameters: 30.6’ Sextant index correction: -3.3′ Navigation Worksheets. here's his routines, Here are some VBA functions that I created. The data for the following example are from John Karl’s “Celestial navigation in the GPS age” (First Edition, 2007), pp. select "Celestial Navigation". DR position: S 34º 13′, E 161º 43′, Input: select "Celestial Navigation". The basic theory behind Celestial Navigation is ... – A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow.com - id: 61e22b-OWQ2Y LHA : LHA (Local Hour Angle) is the angle between the meridian of the celestial object and the meridian of the observer, LHA = GHA(of celestial object) - Longitude (of observer). A recent trip to Santa Barbara, California, presented me with an opportunity to do some sights and calculations. Dec: (+) 27 429/600 entered in cell D2, Ho from alt_corr.xls cells B13, B14: 26 182/600 entered in cell E2, Intermediate results: 17:46:32       —               56° 57.1′      85° 06.9′      N 21° 19.8′       0.6A         104.1, The single afternoon sight was (this time the sextant’s mirrors were adjusted to eliminate index error): assuming standard atmospheric conditions UT: 02h 19m 14s In January 2015 Mercury is visible just northwest of Venus in the evening sky. Comparisons with the 2017 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2017 without the need for any changes or updates. Comparisons with the 2019 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2019 without the need for any changes or updates. All cells of the workbook are protected except for the yellow user data entry cells. Using standard conditions for temperature and pressure: Height of eye (cells E1, F1): 9 ft 19:57:30    76º 14.8′    76º 35.2′    117º 50.0′     N 21º 08.8′    3.4A            172.5. This group is for those interested in the art and science of celestial navigation. The software is based on macro-enabled Microsoft Excel Worksheets. GHA: 51° 59.4’ Azimuth (cell F6): 15.7 agrees with 16 from the book after rounding. Celestial Navigation. With a ruler, connect the center of the compass with the Azimuth (Zn) mark. 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